Algisin is effective against all types of algae in freshwater aquaria. By reducing nutrient uptake, among other things, algae can no longer grow and eventually die. Aquarium plants can absorb their nutrients through the aquarium bed and are thus spared. Colombo Algisin fights algae and ensures a crystal-clear aquarium! Algisin is effective against all types of algae and contains no copper. Dosage: 1 ml per 20 litres of water, with 100 ml 1000 litres can be treated twice. Always test the aquarium water first and correct if necessary before adding algaecide!